A big chunk of the murders in Sonora occur in the big cities like Ciudad Obregon and Hermosillo, but they still happen in tourist destinations like Puerto Peñasco (Rocky Point). For example, a shootout in Puerto Peñasco last year that claimed six lives, including a police officer, was linked to suspected drug traffickers.

It wasn't that long ago that Sonora and Arizona had similar murder rates. In 2006, there were 10 murders per 100,000 residents in Sonora, and 7.5 per 1,000 in Arizona.

However, the murders in Sonora kept increasing from there, hitting a peak of 738 murders, or a rate of 27 per 100,000 residents, in 2010, according to Mexico's National Institute of Statistics and Geography

Arizona's rate has been around 6 murders per 100,000 residents since 2008.

Meanwhile, while the murder rates in two of Sonora's neighboring states -- Sinaloa to the south, and Chihuahua to the east -- have been much, much higher than in Sonora, murder rates have significantly decreased in those states, according to the National Institute of Statistics and Geography.

Chihuahua, which hit a high with more than 6,400 murders in 2010, had fewer than 2,800 in 2012. Sinaloa, which had a high of 2,423 in 2010, recorded fewer than 1,400 murders in 2012.

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